This is a retrospective, observational cohort study in which researchers will use existing databases to identify a cohort of people experiencing opioid-related harm, and examine health service use among them.

Record linkage studies are increasingly being used to examine outcomes of opioid use. These often make use of opioid treatment databases, such as the NSW Pharmaceutical Drugs of Addiction System (PHDAS), to define a cohort of opioid dependent individuals. A criticism of this approach is that it does not include people who are experiencing opioid-related harms (up to and including opioid dependence), but have not sought treatment. This project will use emergency department and inpatient hospital records to identify this latter group, allowing for an examination of the added value of including this group in research on opioid-related harms.

This project will address an important methodological issue in data linkage research on opioid-related harm. It will also provide evidence to inform the care of people with opioid use disorders by identifying target conditions for early intervention.